A very small fraction of building demolition projects involve the use of explosives. Furthermore, exploding and imploding are not accurate ways to describe the demolition of a building; it's more of a purposeful structural failure that happens causing a building to collapse and come down in a properly designed way on itself, a process that has been done for decades.
If you think that a demolition company shows up and starts tearing a building down; that's not how it's done. Steps are carried out to clear the way for a demolition project including careful study of local regulations, asbestos abatement, ensuring the removal of hazardous materials, an examination of immediate surroundings, and clearances from utilities and roadways.
With smaller buildings, such as storage facilities, garages and houses that are only two or three stories high, the demolition challenges are somewhat simpler. The building can usually be taken down by manual or mechanical pulling using bigger hydraulic excavating equipment. Machines you may be more used to seeing such as cranes, specialized excavators or bulldozers.
As we get into larger structures, the use of a wrecking ball, may be used to swing into the side of the buildings where you see masonry walls. While effective, they are very difficult to control and are not as efficient as some newer methods that are being used. These more recently developed methods can use rotational hydraulic shears (looking like a dragon's mouth), and silenced rock-breakers which are attached to excavators.